Sandblasting stencil and method of making same



D OF MAKING SAME Jan. 27, 1942. c. E. FRLCK SANDBLASTING STENCIL AND METHO Filed May 8, 1959 way of an adhesive. flowers, leaves,- or objects are marked on the.

Patented Jan. 27, 1942 snnnmns'rmc STENCIL AND much or MAKING SAME Carl E. Frick, Chicago, 111., assignor to Van Cleef Bron, a partnership consisting of Noah Van Cleef, Felix Van Cieef, and Paul Van Cleef,

Chicago, Ill.

Application May 8, 1939, Serial No- 272,323

11 Claims.

The present invention relates to stencils for use in cutting letters, symbols or designs on monument forming stones or other stone-work by way of sand blasting.

There are now in use two types or methods of stone cutting or carving. One of these is known as ordinary cutting or carvingand consists in first securing a stencil sheet by way of an adhesive to the part of the stone to be cut, then marking or penciling on the front face of the sheet the desired letters, symbols or designs, and finally, after removing from the sheet the marked letters, symbols or designs, directing a blast of sand or other abrasive material through the cutouts in the stencil sheet in order to cut the stone in the desired manner. The other type or method is known as shape cutting or carving. This involves the cutting or carving in the stone of flowers. leaves, or other objects having irregular outer surfaces. In connection with shape cutting or carving, a stencil sheet oi sand resistant materlal is secured against th stone to be cut by Thereafter the desired outer face of the sheet and the marked portions necessary stretching to cover the surface irregularities completely that they do not adhere properly and in many cases are blown off by the flnal sand blast. It has also been proposed to employ as a stencil, a sheet having apermanently tacky inner adhesive facing and formed of uncured or unvulcanized rubber. Such a stencil although of the stencil sheet are cut with a knife or other instrument and thenremoved. At the conclusion of this operation the cut-out or exposed portions of the stone are shaped to the proper flower, leaf, or object configuration by way of an abrasive blasting tool with a small discharge orlflce or by a hand tool. After this step the remainder of the stencil sheet is removed from the stone and the cut-out pieces are placed back over the shaped flowers, leaves or other objects. To conclude the cutting or carving the portions around the cutout pieces are sand blasted to the proper or de-' glue or shellac for toughening the sheet and rendering it substantially inelastic. Such a stencil has been found in practice to beextremely durableand sand resistant'and efficiently fulfills its purpose in connection with ordinary cutting or carving. It is, however, ineflicicnt or diiilcult to 1 use employ in connection with shape cutting unnerving because when the cut-out pieces from the stencil sheet are placed back against the in regular surfaces of the cut flowers or leaves prior tothe flnal sand blasting operation, such cut-out pieces are subjected to such strain due to the nently tacky pressure sensitive rubber base admore particularly deflned useable in connection with regular or shape cutting, is objectionable or defective because it does not possess the desired or necessary resistance to the abrasive action of the blast.

' One object of the invention is to provide a stencil which is an improvement upon each of the aforementioned types of stencils by reason of thefact that it comprises a thin outer layer with vulcanized rubber therein and a thin inner layer having uncured or unvulcani'zed rubber and hence is not only useable in connection with both types of cutting but also is sufllciently wear or sand resistant emciently and effectively to'fulflll its intended purpose.

Another object of the invention is to provide a method of making the improved stencil which may be carried out expeditiously and cheaply and includes.flrst; calenderlng on a sheet of holland a plastic mass including milled rubber with a vulcanizing agent therefor, then calendering onto the exposed surfac ofthe first mentioned mass 9. plastic mass having rubber therein but no vulcanizin'g agent for the rubber, then 7 subjecting the two masses onthe sheet to a vulcanizing temperature in order to vulcanlze the rubber content or portion of the flrst mentioned mass and render the composite sheet of proper hardness, then applying by calenderlng. or spreading on the outer face of the layer with unvulcanized rubber therein, a coating of permahesive and then applying a sheet of holland over the adhesive coating for covering or protective purposes and at the same time removing the flrst mentioned sheet of holland. v

Other objects oi the invention and the various advantages or characteristics of the present stencil and its method of manufacture will be ap-- parentfrom a consideration of the following detailed description.

The invention consists v features which are hereinafter set forth and are clusion hereof. g

In the drawing which accompanies and forms a part of-this speciflcation or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

in the several novel by claims at -the-.con-.

Figure 4 is a section showing the holland sheet' of Figure 3 having calendered onto one face thereof the plastic vulcanizable mass;

Figure 5 is a section showing the non-vulcanizable plastic mass calendered onto the plastic vulcanizable mass;

Figure 6 is a section showing the stencil after the vulcanizing operation and with the adhesive coating on the exposed face of the inner or unvulcanized layer; and

Figure '7 is a section showing the completed stencil after removal of the original holland sheet and application of the protective sheet of holland to the adhesive coating.

- The stencil which is shown in the drawing con- I stitutes the preferred embodiment of the invention. It is illustrated in connection with a stone S and serves, as hereinafter'described, to control a blast of sand or other abrasive material in connection with the cutting or formation of letters, symbols or designs on the stone. As shown in Figure '7, the stencil comprises as its parts an outer layer 8, an inner layer 9, a coating II on the back or exposed face of the layer 9, and a protective sheet I l of holland for the coating Ill. The outer and inner layers constitute a composite sheet and serve as the sand or abrasive controlling medium of the stencil. The coating as hereinafter described is formed of permanently tacky pressure sensitive rubber base adhesive and is adapted after removal of the holland sheet H to secure in place the composite sand-resistant sheet consisting of the outer and inner layers 8 and 9. Said composite sheet is adapted when the stencil is in place on the stone 8 to have the desired letters, symbols or designs marked thereon and then cut-out or removed from it by a knife or similar sharp instrument. When a blast of sand or other abrasive is directed against the stencil during use of the latter, the composite sand resistant sheet serves to control the sand so that it encounters only the portions of the surface of the stone behind the cut-outs and hence cuts by its abrasive action the desired letters.

symbols or designs in the stone. The stencil. as

hereinafter described, has the desired sand or abrasive resisting properties and is useable in connection with not only regular cutting or stone carving but also shape cutting.

The layer 8 includes as its main or principal constituents vulcanized rubber and an admixture of glue or shellac. -It is referably made of the following ingredients in substantially the proportions or amounts specified:

Ingredients Pounds Ounces Smoked rubber sheetsihard tough plantation type rubbe Pearl glue or shellac hill Acc leragor (tetramethyithiuram disulphide)..

Zinc Mi e cocco H oac-aocc together in a heated roll type mill and then while in the form of a plastic mass are calendered onto a sheet I! of holland. Preferably the mass is spread over the holland sheet l2 until ithas a thickness of approximately of an inch, The whiting content of the material acts as a stiffener and a filler and the petrolatum serves as a dispersing or softening agent and to make the 'mass more workable. The sulphur constitutes the vulcanizing agent for the rubber and the tetramethylthiuram disulphide operates as an accelerator for the vulcanizing agent. The zinc oxide content of the material operates to activate the accelerator and the glue or shellac serves to toughen the mass or material as a whole and in addition to reduce the elasticity or recovery properties of the rubber. If shellac is used instead of glue slightly more sulphur is employed and petrolatum, the softening agent, is omitted.

-If desired, fillers other than whiting may be employed such as barytes, clay or starch, or the .flller may be dispensed with. Instead of using equal parts of rubber and glue or shellac in connection with the formation of the layer 8, the rubber and glue or shellac content of the sheet may be changed by employing 40 to ,60 parts of rubber and 60 to 40 parts of glue or shellac. In other words, in the aforementioned formula for the mass from which the layer 8 is made, from 40 to 60 pounds of rubber may be used and from 60 to 40 pounds of glue or shellac may be used.

The layer 9 includes as its main parts or constituents unvulcanized or uncured rubber and an admixture of glue or shellac for toughening purposes. It is preferably made of the following ingredients in substantially the proportions specified:

In connection with the fabrication or formstionof the layer 0, the last mentioned ingredients are milled and mixed together in any suitable manner to form a plastic mass and this mass is calendered onto the exposed face of the mass previously calendered onto the holland sheet 12.

" for rendering the rubber inelastic.

Preferably the mas which serves to form the layer s is spread over the first calendered mass until it has a thickness of approximately "limo of an inch. The whiting content of the mass which is used to form the layer 0 serves as a stiffener and a filler and the glue or shellac serves a a toughening agent and also a medium The alum serves as a retarder, that is. as a medium for preventing vulcanization of the rubber content and the palm oil acts as a softener and to dis- After the last mentioned vcalendering or spreading operation, the holland sheet I! with the'two plastic masses thereon, is placed in an oven or other heating apparatus and is subjected to a temperature of approximately 200 F. for about eighteen hours. This serves to form the composite sand resistant sheet and causes vulcanization of the rubber content of thelayer 8. Because of the use of alum or a like retarder in the mass which unvulcanized condition. By having rubber in the outer layer 8 the composite sheet as a whole-has the desired or necessary resistance rubber and glue or shellac it resists any abrasive or wearing effect of the sand and hence the portions of the stencil which remain after the letter or design cutting operation protect the contigu ous portions of the surface of the stone from abrasion by the sand. After the sand blasting endering or spreading operation after the vulcanizlng step. It is .essentially permanently tacky and is preferably formed of the following ingredients in substantially the proportions specified:

' Ingredients Pounds Ounces Milled white crepe rubbert as Zinc oxide l2 Burgundy pitch... 18 Oregon balsam. l

The Burgundy pitch content of as adhesive serves as the softener and makes the adhesive extremely tacky. The oregonbalsain due to'the fact thatit is non-volatile makes the-adhesive permanently tacky. After application of the adhesive coating Ill to the exposed face of the layer 9 of the composite sheet, the sheet ll of holland is applied to the. exposed face of the coating. This sheet it corresponds in size to the coatirig and serves to prevent the latter from adhering to objects prior to use at the stencil. During or after application of the holland sheet if to the permanently tacw pressure sensitive adhesive coating 80 the holland sheet 82 on the layer B is removed. By reason of the fact that the coating 10 isin the form of a permanently tacky pressure sensitive rubber baseadhesive the stencil may be readily. applied to the work, that is, the surface to be cut, withouta preliminary .a'z 'wetting or molstening operation, and may be readily removed after the sand blasting step. The coating serves as a cushion type backing absorbing the shock or impact of the sand as it impinges against the sheet increases materially the lasting properties of the sheet. Another feature or advantage of employing. acoating of pressure sensitive adhesive resides in the fact that the composite sheet .is flrmly' held in place against the work during the sand blasting operation and may, if desired, be removed and then reapplied.

' two different forms or types of stencils for the operation, the stencil is stripped or peeled from the cut surface. If the stencil is used in connection with shape carving of .the stone S it is applied to the stone by way of the adhesive coating ill. Thereafter the front or outer face of the outer layer 8 is marked with any desired designs such as flowers or leaves, and the flower or leaf portions are cut out. After this stepthe exposed portions of the stone within the confines of the' stencil are suitably shaped by way of an abrasive blasting tool witha small discharge orifice or by a hand too]. After the proper shaping'of the' flowers or leaves the stencil is removed and the cut-outs are placed back on the flowers or leaves.

At the conclusion of this step the portion of the stone around the flowers or leaves are sand blasted to the desired depth to bring the flowers or leaves into relief. By reason of the factthat the composite sand resistant sheet includes the layer 8 with uncured or unvulcanized rubber therein, the cut-outs when reapplied conform to the surface irregularities of, and adhesively grip,

the previously shaped underlying portions of the stone.

Theherein described stencil maybe produced' at a comparatively low and reasonable cost and because of its composite character is readily useable for shape cutting as wellas regular stone cutting. It eliminates the necessity of supplying two different types of cutting and is an improve- 'ment upon and has certain advantages over the stencil which forms the subject matter of United States Patent No. 2,162,332, granted to me on June 13, 1939, and also the'stencil disclosed in United States patent application Serial No. 271,-

104, flied by me on May 1, 1939.

for the composite sand resistant sheet and by The invention is not to be understood as 'restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

' Having thus described the invention, what I claim as new and desire to secure by'letters Patentis:

.1. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or In using the stencil in connection with regular 'said blasting to form letters on the stone S the holland sheet II is first stripped or peeled'from the coating Ill of pressure sensitive rubber base adhesive. Thereafter thev stencil is pressed against the surface to be cut or. lettered in order to bring the coating 10 into adhesivcly connected relation with the latter. Thereafter the letters or designs to be cut in the stone 8 are penciled orotherwise marked on the front face of thelayer 9 and are cut out or removed by a sharp knife or like tool.-

controls the sand'so'that it-encounters only the portions of the surface bf the stone S.,behind the cut-outs and hence cuts by its abrasive action the desired letters in the surface. By reason of At the conclusion of thisv operation sand is blasted against the layer 3. During the sand blasting operation the sheet layer embodying an appreciable amount of uncured rubber in it, and an adhesive coating on.

designs on a surface by way of anabrasiveblast and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or cuts the desired letters, symbols or designs on 7 said surface-and including an abrasiver istant outerlayer formed of an appreciable am nt ofvulcanized rubber and an admixture -of a ma-' terlal serving-to render said vulcanized rubber tough and substantially ine1astic,.and an inner the fact that the outer layer of the composite sheet is formed of a composition of vulcanized ing thereof to control the blast so that it forms or cuts the desired letters, symbols or designs on said surface and consisting of an abrasive resistant outer layer including a substantial amount of vulcanized rubber and an admixture of a material serving to toughen the rubber and make it substantially inelastic, and an inner layer including a substantial amount of unvulcanized rubber in it and a medium for-making said unvulcanized rubber tough and substantially inelastic, and an adhesive coating on the exposed face of the inner layer for holding the sheet in adhesively connected relation with said surface.

3. -As a new article of manufacture, a stencil designed for use incutting letters. symbols or designs on a surface by way of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or cuts the. desired letters, symbols or designs on said surface and consisting of an abrasive resistant outer layer embodying an appreciable amount of vulcanized rubber and an admixture of a material whereby said vulcanized rubber is rendered tough and substantially inelastic, and an inner layer embodying an appreciable amount of uncured rubber and serving to make the sheet as a whole appreciably flexible and capable of setting to the proper extent for shape cutting, and a coating of permanently tacky pressure sensitive rubber base adhesive applied to and completely covering the exposed face of the inner layer and adapted to hold the sheet in adhesively connected relation with said surface.

4. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or designs on a surface by way of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or cuts the desired letters, symbols or designs on said surface and consisting of a comparatively thin abrasive resistant outer layer embodying a substantial amount of vulcanized rubber and an admixture ofa material serving to render the vulcanized rubber tough and substantially inelastic, and an inner layer of less thickness than the outer layer embodying a substantial amount of unvulcanized rubber in it and in addition an admixture of the same material that is in the outer layer whereby said unvulcanized rubber is also rendered tough and substantially inelastic, and an adhesive coating on the inner layer for holding the sheet in adhesively connected relation with said surface.

6. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or designs on a surface by way of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or .cuts the desired letters, symbols or designs on said surface and consisting of an abrasive resistant, tough, substantially inelastic, outer layer and an inner layer including a substantial amount of unvulcanized rubber and an admixture of a toughening agent selected from the group composed of glue and shellac, and an adhesive coating on the exposedface of the inner layer for holding the sheet in adhesively connected rela-' tion with said surface.

7. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or designs on a surface by way of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or cuts the desired letters, symbols or designs on said surface and consisting of an abrasive resistant outer layer including a substantial amount of vulcanized rubber and an admixture of a toughening agent selected from the group composed of glue and shellac and an inner layer including a substantial amount of unvulcanized rubber and an admixture of a toughening agent selected from the aforementioned group, and an adhesive coating on the exposed face of the inner layer for holding the sheet in adhesively connected relation with said surface.

8. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or designs on a surface by way'of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms or cuts the desired letters, symbols or designs on said surface and consisting of an abrasive resistant outer layer including a substantial amount of vulcanized rubber and an admixture of substantially an equal amount of a toughening agent selected from the group composed of glue and shellac. and an inner layer including a substantial amount of unvulcanized rubber and an admixture of substantially the same amount of a toughening agent selected from the aforesaid the exposed face of the inner layer for holding the sheet in adhesively connected relation with said surface.

5. As a new article of manufacture, a stencil designed for use in cutting letters, symbols or designs on a surface by way of an abrasive blast, and comprising a composite sheet adapted to be placed against the surface and upon proper shaping thereof to control the blast so that it forms and an adhesive coating on the exposed face of group, and a coating of permanently tacky pressure sensitive rubber base adhesive applied to and covering the inner face of the sheet and adapted to hold the sheet in adhesively connected relation with said surface.

9. That improvement in the manufacture of a stencil which comprises first forming into layer form and uniting together in side by side relation two plastic masses, one of which includes a substantial amount of milled rubber and toughening agent, and a vulcanizing agent for the rubber, and the other of which includes a substantial amount of milled rubber and toughening agent, and a vulcanizing retarder for the last mentioned rubber, then heating the two layers in order to vulcanize the rubber of the one mass and form a tough sand resistant composite sheet, and then applying an adhesive coating to the exposed face of the layer formed by the other mass.

10. That improvement in the manufacture of a stencil which' comprises first forming into a thin layer a plastic mass including a substantial amount of milled rubber and toughening agent,

composite sheet, and then applying an adhesive coating to the exposed face of the second layer.

11. That improvement in the manufacture of ,a stencil which comprises first spreading into a layer form on a sheet oi holland type material a plastic mass including milled rubber and a toughening agent, and a 'vulcanizing agent'for 15 the rubber, then calendering into layer form onto the exposed face of the yer formed by said mass 9. second plastic mass eluding a substantial amount of milled rubber'and toughening agent,

and a vulcaninng retarder for the last mentioned rubber, then heating the two layers in order to vulcanize the rubber of the first layer and form a sand resistant composite sheet, then applying a coating of permanently tacky pressure sensi-- 1o'tive adhesive to the exposed face of the layer 1 formed by the second mentioned mass, and then applying a sheet of holland type material over the adhesive coating and removing the first mentioned sheet of holland type material,

CARL E. FRICK. 

